Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Quantos oponentes têm Wimbledon (2) como o campeonato?
 ###Tabelas: CREATE TABLE points_system (points_system_id AUTO_INCREMENT PRIMARY KEY, Distance VARCHAR, 10th INT, 11th INT, 12th INT, 13th INT, 14th INT, 15th INT, 16th INT, 17th INT, 18th INT, 19th INT, 20th INT, 21st INT, 22nd INT, 23rd INT, 24th INT, 25th INT, 26th INT, 27th INT, 28th INT, 29th INT, 30th INT, 31st INT, 32nd INT) CREATE TABLE lightweight_manx_grand_prix (lightweight_manx_grand_prix_id AUTO_INCREMENT PRIMARY KEY, Rank INT, Rider VARCHAR, Team VARCHAR, Speed VARCHAR, Time VARCHAR) CREATE TABLE doubles:_37_31–6 (doubles:_37_31–6_id AUTO_INCREMENT PRIMARY KEY, Outcome VARCHAR, Year INT, Championship VARCHAR, Surface VARCHAR, Partner VARCHAR, Opponents VARCHAR, Score VARCHAR) CREATE TABLE year-by-year (year-by-year_id AUTO_INCREMENT PRIMARY KEY, Year INT, Record VARCHAR, Regular Season Finish VARCHAR, Playoffs VARCHAR, Avg Attend. INT) CREATE TABLE 2005_ladder (2005_ladder_id AUTO_INCREMENT PRIMARY KEY, Golden Rivers VARCHAR, Wins INT, Byes INT, Losses INT, Draws INT, Against INT)  
SELECT COUNT Opponents FROM doubles:_37_31–6 WHERE Championship = Wimbledon (2)